Hi. I'm using a mask to 'prevent' access to 3 gridpanels which are in an accordion.

For each grid, on the 'render' event, I'm creating the mask. The mask works fine for the first grid (top panel which is open in the accordion), and then fine for the first time I open the 2nd and 3rd panels to view the grids, but on subsequent openings of the 2nd and 3rd panel, the mask element has been shifted down a whole lot (the 'top' value is around 300px larger, and stays like that regardless of how many times I re-open the panel).